Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int arr[505][505], temparr[505][505];
int main() {
  int n, m;
  scanf("%d %d", &n, &m);
  int i, j, sum = 0, check = 0;
  memset(arr, 0, sizeof arr);
  memset(temparr, 0, sizeof temparr);
  for (i = 0; i < n; i++) {
    for (j = 0; j < m; j++) {
      scanf("%d", &arr[i][j]);
      sum += arr[i][j];
    }
  }
  int flag = 0;
  if (n > m) {
    for (i = 0; i < n; i++) {
      for (j = 0; j < m; j++) {
        temparr[j][i] = arr[i][j];
      }
    }
    memset(arr, 0, sizeof arr);
    swap(n, m);
    for (i = 0; i < n; i++) {
      for (j = 0; j < m; j++) {
        arr[i][j] = temparr[i][j];
      }
    }
    flag = 1;
  }
  int c = 0, row[50000], col[50000];
  int mini = 505, x = 0, y = 0, z;
  for (i = 0; i < n; i++) {
    mini = 505;
    for (j = 0; j < m; j++) {
      if (arr[i][j] < mini) mini = arr[i][j];
    }
    c += mini;
    if (mini > 0) {
      for (z = 0; z < mini; z++) {
        row[x] = i;
        x++;
      }
    }
    for (j = 0; j < m; j++) {
      arr[i][j] -= mini;
    }
    check += mini * j;
  }
  for (j = 0; j < m; j++) {
    mini = 505;
    for (i = 0; i < n; i++) {
      if (arr[i][j] < mini) mini = arr[i][j];
    }
    c += mini;
    if (mini > 0) {
      for (z = 0; z < mini; z++) {
        col[y] = j;
        y++;
      }
    }
    for (i = 0; i < n; i++) {
      arr[i][j] -= mini;
    }
    check += mini * i;
  }
  if (check == sum && flag == 0) {
    printf("%d\n", c);
    for (i = 0; i < x; i++) {
      printf("row %d\n", row[i] + 1);
    }
    for (i = 0; i < y; i++) {
      printf("col %d\n", col[i] + 1);
    }
  } else if (check == sum && flag == 1) {
    printf("%d\n", c);
    for (i = 0; i < x; i++) {
      printf("col %d\n", row[i] + 1);
    }
    for (i = 0; i < y; i++) {
      printf("row %d\n", col[i] + 1);
    }
  } else
    printf("-1\n");
  return 0;
}